Sealing means for submersible structures



July 28, 1942.

T. G1 MYI-:Rs

SEALING MEANS FOR SUBMERSIBLE STRUCTURES Filed Feb. '28, 1958 5 Sheets-Sheet l July 28, 1942. T. G. MYERS SEALING MEANS FOR SUBMERSIBLE STRUCTURES Filed Feb. 28, 1958 5 Sheets-Shes?l 2 July 28, 1942- IT. G. MYERS 2,291,248

SEALING MEANS FOR SUBMERSIBLE STRUCTURES C '72 m fm \NVENTOR Thomas C. M ers BY g f ATTO R N EY .July Z8, 1942. T G, MYERS y SEALING MEANS FOR SUBMERSIBLE STRUCTURES 5 Sheets-Sheet 4 Filed Feb. 28, 1938 Titi. 1E]

I INVENTOR Thornds wi BY y M ATTORNEY July 28, 1942. T. G. MYERS 2,291,248

SEALING MEANS FOR SUBMERSIBLE STRUCTURES Filed Feb. 28, 1958' 5 sheets-sheet 5 ISI INVENTOR Thomas G1. M ers ATTORNEY Patented July 28, 1942 SEALING MEANS FOR SUBMERSIBLE STRUCTURES Thomas G. Myers, Los Angeles, Calif., assignor to U. S. Electrical Motors, Inc., Los Angeles, Calif., a corporation of California Application February 28, 1938, Serial No. 193,120

8 Claims.

This invention relates to submersible structures, such as electrical motors adapted to be lowered into well" liquid for direct connection to a pump. The motors are usually of the induction motor squirrel cage rotor type.

Structures of this general character have been described in several otherapplications led in the name of Thomas G. Myers and identified as follows:

Submersible structure, Serial No. 173,434 filed November 8, 1937;

Sealed submersible structures, Serial No. 175,896, filed November 22, 1937.

These structures invariably include a casing having provisions for excluding the well liquid, at least from that portion of the casing which carries the electrical windings and the bearings for the rotary portion of the structure. The provisions may include a filling of neutral liquid,

such as oil or carbon tetrachloride, or a gas.,

in the casing; and an appropriate seal to prevent entry of well liquid around the shaft where it extends from the casing.

It is one of the objects of this invention to provide a simple and yet effective sealing means around the shaft.

For this purpose, the seal is provided by the aidvof an appropriate resilient sleeve or member that closely surroundsthe shaft. It is made from material that resists deterioration by the liquids with which it is in contact. Such material, for example, may be oil resistant rubber or fabric. Accordingly it is another object of this invention to provide a seal of this character.

In some instances it may be desirable to supplement the seal by a liquid seal encompassed within the sleeve and in contact with the shaft. It is another object of this invention to make it possible to provide such a supplemental seal.

It is another object of the invention to provide a liquid seal, such as mercury, in which the .liquid extending around the shaft may be placed under a constant pressure, causing it to be urged more securely into sealing relation to the shaft.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose, thereare shown a few forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention.; butit is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a view, mainly in longitudinal section, of a device incorporating the invention, shown as submerged in well liquid;

Fig. 2 is a fragmentary sectional view of an apparatus similar to that shown in Fig. 1, but of a modied form of the invention;

Fig. 3 is an enlarged sectional view taken along plane 3-3 of Fig. 2;

Fig. 4 is a view similar to Fig. 1, 'but of a further modifled form of the invention;

Fig. 5 is a fragmentary sectional view, similar to Fig. 4, but of a further modified form of the invention;

Fig. 6 is a view similar to Fig. l, of another form of the invention;

Fig. 7 is an enlarged fragmentary detail sectional view of a portion of the seal shownin Fig. 6;

Figs. 8, 9, 10 and 11 are fragmentary sectional views illustrating modified forms of seals;

Fig. 12 is a detail sectional view on an enlarged scale of the pressure regulator used with the seal of Fig. 6; and

Fig. 13 is a view of a similar pressure regulator used in a slightly different manner.

In Fig. 1, the well is shown as defined 'by well casing I, having well liquid 2 therein. This well liquid may be water or the like.

Submerged within the well liquid 2 there is a casing 3 in which is disposed an electric motor I. This electric motor may be of a conventional induction motor squirrel cage type. It is shown as provided with the primary windings 5, supported on laminations 6, in turn supported by the wall of casing 3. The rotor 1 is shown as mounted on the rotary shaft 8, which extends in this instance upwardly out of the casing 3 for direct connection to a pump (not shown).

The shaft 8 is shown in this instance as suD- ported by upper and lower ball bearing structures 9 and l0 respectively. The ball bearing structure 9 is shown as having its outer race mounted in the central hub of a spider II. This spider I'I has a ange I2, by the aid of which it may be fastened to the flange I3 extending inwardly of the casing 3.

The lower ball bearing structure I0 is shown in this instance as having its outer race supported in the central boss I4 of a spider I5 extending acmss the bottom portion of the casing 3.

In. order to exclude well liquid from the caspresent instance by the use of an annular closely fitting sleeve i1, supported on the top I.. as by the bolts Il, which pass through a base iis-nge formed on the sleeve. This sleeve i1 is purposely made of resilient material which is slightly expanded when the shaft I is passed throlllh it. As examples of such material may be mentloned oil-prooi rubber or woven flexible fabric in which ela'stic elements maybe used to provide a compression force on the shaft l. Suibeimpervioustowatensineaiiitissoakedwith thesameneutralliquidasisusedtoilllthe casing, it will be eiectlve w prevent intermixtureoi'thewellliquidandtheiiquidinthe casing. Thus,ii'thecesingisiilledwithoil. fabricsoakedinoilshouldbeusedandlfcarbon tetrachlorideisused,toilllthecasing,thefabric shouldbesoakedincarbontetrachloride. A filler pipe i9 is indicated, whereby the iilling agg@ s Era volume chamber 2l serves to insure that pressureswithinandexterlorofthecasing will be substantially the same. Upon a reduc tion of interior pressure, the bellows 2l is suiiiciently compressed to increase the interlo pressure by appropriate reduction in volume: and

pressure within the casing l, th'e variable volume chamber 2l is expanded until substantial equality is secured.

It may be desirable frequently to maintain thepressurewithlnthecasinginexcessoftbe pressure prevailing outside. In this case, a spring loaded relief valve, such as to be presently disclosed in connection with Fig. 4, may be substituted for chamber 2|, the neutral liquid being ing l, provisions are made-to seal aroundv the l shaft". Whle if extends thl'OuUh the top il -ofthiscaslng3.*Thisisaccomplishedinthe or a pressure regulatorsuch as disclosed in entitled Submersible structure," Serial No 173,434, nled November s, 1937, may be used.

Inthetorm ot the invention illustratedinl'igs. 2and3,tbetopllofthesubmersiblecaaing lisshowmasbeioraassupportingaresilient 2l. 'I'hisannularreeessprovidesanannnlar chambertheshaitlin recessandsecurelyioinedtotheiiexiblemenbex-2|. Aiillerpipellmaybe'conneetedtothe bushing.

incontactwiththesealinglimnkillortbeaealof the invention also, to insure that the pressure within the casing 32 will be maintained at about the same value as that due to the gravity head of the well liquid. To insure against undue pressure rise within the casing, a conventional relief valve mechanism 44 may be provided. This valve'mechanism is intended to open and release some of the neutral filling, should the pressure within the casing 32 reach an undesired high value.

In the form of the vinvention illustrated in Fig. 5, the yielding or resilient sleeve 45 is again shown as depending outwardly. and downwardly of the casing cover 39. In this form of the invention, a body. of heavy sealing liquid, such as mercury, may be interposed in the annular recess 41 formed in the member 45 and providing an annular chamber around the shaft 34. The shaft 34, as indicated by the layer 4l, may be provided with an inert protective coating, such as mentioned hereinbefore. If desired, several annular coil springs 49 may be provided to serve as a supplemental means for urging the sleeve member 45 against the shaft 34.

In this case also, a metal bushing I is shown as leading into the recess 41. This bushing serves to permit filling of this recess with the sealing liquid 46. It may be provided with a ller pipe 5|, including a check valve 52 to prevent return flow of the sealing liquid from recess 41.

In the form of the invention illustrated in Figs. 6 and '7, a well is shown again as defined by well casing l. In this Well casing is well liquid 2, almost invariably water, which it is desired to remove by the aid of a pump, not shown.

In order to drive the pump, use is made of an electric motor 55, shown as enclosed in a fluid tight casing 56. The fluid tight casing 55 is intended to be lowered in the well and from it extends a rotary shaft 51. This shaft is intended to be directly connected to the pump.

The casing 56 is indicated as of genera-.l cylindrical construction. The stator or primary windings 58 are shown as supported in laminations 59 fastened to the inner wall of the casing 56. The rotor 60, which may be of the conventional squirrel cage type, is shown as fastened to the shaft 51. This shaft 51 is shown as rotatably supported by the aid of ball bearing structures. Thus, at the lower end of the shaft, the ball bearing structure 6| has its inner race supported on a reduced portion of the shaft 51. Its outer lrace is supported in a boss 62 formed within a spider 63. This spider 63Ais shown in this instance as integral with a cap or bottom cover 64 threadedly engaged with the main casing shell.

Adjacent the upper end of the rotor EQ, the ball bearing structure 65 is shown as having its inner race supported on shaft 51 by means of an inverted cup 66. Its outer race is supported in a removable spider 61, which includes a -well 58 for the purpose of providing lubrication for the bearing and adapted to be supplied with lubricant by means of the tube |65, extending to the top of the well. This spider is shown as attached to the integrally formed flange 69 extending inwardly from the wall of casing 56.

The top of the casing in this instance is shown as formed by a cover member 1|) fastened in fluid tight manner to the upper edge of the casing 56. It is provided with a clearance aperture 1| for the upward passage of the shaft 51. The manner in which the well liquid 2 is prevented from entering around the shaft 51 through aperture 1| will now be described.

The seal for shaft 51 includes a non-rotary member 12, which is of yielding material, such as impregnated felt, rubber, or the like. This member closely encompasses and contacts the shaft l1 by its natural elasticity. It is fastened to the top 1l in fluid tight manner, as by the aid of its flange 13, through which the fastening means 14 are intended to pass.

This sleeve-like non-rotary' member 12 is shown in this instance as extending upwardly and outwardly of the casing 56, although this arrangement is not absolutely essential. Intermediate the top and bottom of the rotary member 12 an annular recess 15 is formed. In this recess a sealing liquid 15, such as mercury or the like.' is intended to be placed, as by the aid of a feed pipe 11, which is connected to a receptacle 15 at the top of the well containing the sealing liquid under suitable pressure, a pressure regulator 1I being interposed between the receptacle 15 and the seal. This is shown as mounted on the cover 1l oi' the motor casing,l and may be enclosed in a protective casing, if desired.

The mercury 15, having a high surface tension, forms an effective obstacle to the passage of well liquid along the shaft 51. Since the body of mercury 16 may exhibit active chemical properties, it is preferable to provide an inactive or inert layer Il on that portion of shaft 51 which is in cooperative relationship with the seal. Such a layer may be ceramic enamel or other inert material, such as varnish or the like.` In this way amalgamation with the body of mercury Yis effectively prevented.

The pressure of the well liquid, of course, normally acts in a radial direction to compress the sleeve-like non-rotary member against the shaft 5l, and thereby to assist in the sealing effect.

In order to enhance the effectiveness of the sealing liquid T6 and to tighten the seal, provision is made to maintain the pressure of the sealing liquid above the pressure of the Well liquid surrounding the seal. This ensures that any leakage occurring will be outwardly from the seal and not from the well inwardly. It is desirable that the pressure of the sealing material exceed that of the well liquid at all times by relatively smail predetermined amount or differential. As the height of fluid above the casing may vary within rather wide limits, depending on several conditions, among them the operation of the pump, a convenient way in which this may be done is by the provision of the pressure regulating device 1U, supported near the seal and subject to the well liquid pressure.

As previously mentioned, the liquid sealing material 16 is supplied under pressure from a. receptacle 19, conveniently located at the top of the well, in regulated amount through conduit 11. The automatic pressure control is effected by a pressure regulator 18 interposed in this conduit, and which is shown in greater detail in Fig. l2.

Frame 1|! of regulator 18 has an inlet VH and an outlet |12. on opposite sides of a dividing wall H3. This wall supports a member |14, as by screw threads forming a valve seat |15. A valve closure |15 cooperates with the valve seat and is urged to closing position, as by the spring |11 heid in cage |18. There are, however, additional opposing forces acting to open the valve, which forces act to ensure that the pressure of the well liquid adjacent the seal, plus an added pressure, exists on the liquid 16 in the space 15 within the seal.

This closure |15 is fastened to a stem |19 extending through member |14. At its upper end stem |18 is fastened to a guide Ill joined to a diaphragm lli. This diaphragm can be metal or leather or the like, and can be held in place by a cover member Il! apertured as at Ill to permit the well pressure to be exerted on the upper surface of the diaphragm. supplementing the external pressure of the well liquid is the pressure of a compression spring lu. This spring has a guide or shoe Ill resting on the diaphragm lll, and its upper end rests against a support IIS. The pressure of the spring is adjustable by the aid of a set screw I" in cover |82 to provide an adjustment of the total pressure on diaphragm iii. posed to the opposing pressure in space 'Il via conduit Ill.

It is apparent that the diaphragm III urges the valve to open when the combined pressure of the spring and well liquid acting on its upper surface exceeds the pressure of the liquid in the seal, acting on its lower surface. Thus, the pressure on the liquid 18 in the seal exceeds that of the surrounding well liquid by a predetermined amount, this amount being regulated by the adjustment of spring I, If any oi' the liquid escapes from the seal. as by leakage, so that the pressure is reduced, valve opens and admits additional liquid until the pressure is again established at the predetermined amount.

Since the sleeve 12 is formed of non-rigid material, expansion and contraction of liquid 16 in accordance with temperature variations is accommodated without the attainment of excessive pressure. As the volume of trapped liquid in the seal is small, any change in volume will be slight. To reinforce sleeve I2 and add resilience to it when the sealing liquid is confined, springs H2, similar to the springs shown in Figs. 2 and 3, surround space 15.

Where the pressure within the motor casing is maintained above that of the surrounding well liquid, as mentioned in connection with Figs. l and 4, it may be desirable to have the pressure of the liquid 16 maintained at a predetermined differential with respect to the pressure within the casing. In this case. it is only required to permit the pressure of the casing fluid to act on the upper side of diaphragm III. This may be readily accomplished by placing the device 1l oi' Fig. l2 interiorly of the motor casing, when the pressure of the casing fluid would be effective on the diaphragm through ports |83.

Or .'.s illustrated in Fig. 13, the regulator 1l may be mounted exteriorly of the casing |89, and provided with a. fluid tight cap I, in place of the ported cap. A tube ISI connects the interior of the cap with the inside of casing IBI, permitting the fluid pressure within the casing to act on the upper side of diaphragm lli. As the regulator is the same as that previously described in all other respects, obviously it will act to maintain the pressure on liquid 16 at the predetermined amount above the pressure of the fluid within the casing.

It may be desirable to provide a gaseous atmosphere within casing 58 for the motor to operate in, thereby reducing the friction losses incident to the rotation of the rotor in a liquid. as in the previously described forms. Thus a pipe 8l may lead from casing 5i to source of air or neutral gas, under pressure, indicated at 82. The pressure of this gas must obviously be somewhat greater than the pressure of the well liquid 2 at the depth of the casing, sothat when the The lower surface of diaphragm Ill is ex surce of compressed air is placed in communicationwiththecasing,theairwillexpel theliquid through opening u at the bottom oi' the motor casing.

It is essential that the pressure within the easing be maintained sumcientiy great to keep the well liquid out of the motor. This may readily be accomplished by providing a pressure regulator similar to regulator 1l, so arranged that compressed air is admitted by the regulator into casing It automatically from source I! to keep the pressure in the `casing at a few pounds above the well pressure. Alternatively, where casing l. is provided with an outlet such as the aperture .thepressureinthe casingshouldbe lowenough so that the air will not be forced out of the casing through opening I3. One way in which this can be done is by providing an electrically operated valve Il. regulating the admission of air and controlled by a float operated switch ai.

Stator 5I of motor 55 is shown as connected by leads II and main switch l1 to power mains Il. it being understood that these leads are shown only diagrammatically and in actual practice would be enclosed in a water-proof conduit, joined to the casing in a manner to exclude well liquid.

As it is equally important te keep the level of' the well liquid in casing i. below the motor. regardless oi' whether the latter is yenergized or not, valve I( and switch l5 therefor are included in a circuit which is connected to power mains Il so as to be unaffected by the switch l1.

This circuit may include a step down transformer Il, the primary of which is connected to a pair of the power mains. One side of the secondary may be grounded to the casing Il by lead 9|, the other side oi' the secondary being connected by lead 9| to the solenoid l2 which operates valve u. 'I'he other terminal ofthe solenoid is connected by lead $3 to the stationary contact Il of switch l5. 'Ihe moving contact Il of this switch is carried by float Il. pivoted to the wall of casing Contact is connected to the transformer by being grounded to the casing. as by lead I1.

The arrangement is such that when the surface l. of the liquid within the casing, which liquid serves to support the float, rises to a predetermined point, switch l5 will be closed and complete the circuit through the solenoid l2, energizing the latter and causing it to open valve u. This admits gas under pressure to the casing, which depresses the liquid level, until switch II is opened, permitting valve Il to close in response to the action of spring 99.

To prevent absorption of the air or gas by the well liquid. it may be desirable to provide a layer of light neutral lubricating liquid, such as oil, on top of the well liquid in the casing 58. This liquid layer is indicated by the numeral lill, and has a surface of contact IBI with the weil liquid. Since it is desired to use this layer nf oil to lubricate the lower motor bearing Il, switch Il is placed above the bearing.

It is of course, essential to keep well liquid out of this bearing, and if layer I is to be omitted. switeh Il should be placed below the bearing. In order to prevent the surface Ill oi' the well liquid from reaching bearing 8l. as due to partial loss ofthe oil for any reason, means are provided for replenishing the light neutral liquid whenever this surface reaches a predetermined height. Thus. a container Il! filled with oil imder suitable pressure is connected with casing Il by I conduit |09, which is controlled by an electrically operated valve |01.' This valve is normally maintained closed by spring |66, and is arranged to be opened by energization of a solenoid |61. A

check valve may be provided in the conduit |09 to prevent accidental discharge of oil or gas through the conduit. Means are provided to automatically energize this solenoid. Thus, a member |02, carrying spaced electrodes |03 and |04 is supported on the inside of cap 644. One of these electrodes is connected to transformer 69 by being ground-ed to the casing, while the other electrode is connected to solenoid |61 by lead |05, and the solenoid in turn is connected to the transformer by lead |66. Since the well liquid is a conductor, when it reaches electrodes |03 and |04, the circuit between them and through the transformer and the solenoid will be completed. As the voltage in this circuit may be low, it will be understood that it may be desirable to lnclude some form of relay. Lead 93 and |05 may be placed in the conduit along with motor leads 86. When surface |0| has been suiciently lowered to interrupt this circuit, thereby deenergizing solenoid |61, the flow of oil to the casing is stopped by closing valve |01 in response to spring |66. A lamp |06 can be connected in parallel with the solenoid |61, thus serving to give a visual indication where the'well liquid reaches the predetermined height in the casing. If desired, another lamp may be similarly connected in the circuit with solenoid 92 and give a visual indication when the surface 98 reaches the predetermined height.

In the form of the invention illustrated in Fig. 8, the casing wall 'l0 is again shown as having a clearance aperture 1| through which the pump operating shaft 51 extends. In this form of the invention there are a pair of axially spaced nonrotary members ||3 and ||4 which are made of metal and which have a close t on the shaft 51. The tolerance between the axially spaced members ||3 and y||4 and the shaft 51 may be of the order of .0005 inch.

Joining the two members ||3 and ||4 there is shown a metal bellows structure ||5 within which is disposed a. body of sealing liquid ||6, such as mercury. In this way the two members ||3 and ||4 and the intervening bellows ||,5 define an annular space around the shaft 51, through which any well liquid must pass downwardly in order to reach the interior of the casing. The mercury seal I6 may be placed within this annular space, as for example through an aperture ||1 closed as by a radial screw plug 8 in the upper nonrotary member I4.

'I'he lower non-rotary member |3 is shown as joined in fluid tight manner to the Wall 10, as by the ald of the metal bellows ||9, shown as having the flange |20 fastened as by screws |2| to the top of the wall 10.

'I'he yielding connection ||9 makes it possible for the shaft 51 to have some whipping or radial motion with respect to the axis of the motor without disturbing the sealing effect of the two members ||3 and ||4, `and without causing undesired vibrations in the structure, or undue wear of the closely tted members.

In order to create a supplemental fluid pressure upon the body of mercury ||6, use is made in this instance of a yoke structure |22. This yoke structure |22 is shown as encompassing the shaft 51 above the member ||4. It contacts the diametric knife edges |23, formed on member I4. The radially extending arms |24 and |25 are inupon the member ||4.

tended to be pulled downwardly in a resilient manner, by the aid of the tension springs |26, thereby exerting a downwardly directed force This force, therefore, tends to compress the annular space in which the mercury I5 is located.

The springs |26 may be anchored in any appropriate manner to the arms |24 and |25. For example, this may be accomplished by the eyes |21 attached to the arms. The other ends of the springs |26 may be similarly anchored in the eyes |28 fastened to the wall 10.

Other ways of providing the compressive force may be used. For example, in the form of the invention illustrated in Fig. 9, the non-rotary members |30 and |3| are, as before, joined by the flexible metal bellows |32. These spaced members |30 and |3| are in close sealing contact with the rotary shaft 51. In this instance a feed pipe |33 is ,indicated leading into the annular space in which the liquid seal is to be accommodated.

A check valve |34 prevents reverse flow of the Y v sealing liquid.

In this case the yoke |35 encompasses the upper non-rotary member |3| and is joined to it by the aid of the pins |36 extending radially at opposite sides of the collar |3|. The radial arms |31 of the yoke |35 are provided with through apertures |38 through which the stationary upright studs |39 extend beyond the yoke |35. 'I'hese studs are encompassed by the compression springs |40, urging the yoke downwardly. 'I'he upper ends of the compression springs are confined, as by the washers |4| and nuts |42. By appropriate adjustment of these nuts |42, the compression force acting upon the liquid seal may be adjusted.

In the form of the invention illustrated in Fig. 10, the non-rotary sealing member |44 is shown again as tightly encompassing the shaft 51 extending through the clearance aperture 1| of the casing wall 10. This non-rotary member |44 is shown as supported in a yielding manner upon the wall 10, as by the aid of the yielding metal bellows |45.

The intermediate recess |46 is formed in the member |44, defining an annular space around the shaft 51. In this annular space is located the sealing liquid |41, such as mercury. As before, the shaft 51 may be provided with an inactive layer |48, as of enamel or the like.

In order to tighten the seal by supplemental pressure of the liquid |41, use is made in this form of a spring operated piston. Thus the member |44 is provided with a radial extension |49. This extension is hollow and connects, as by the aid of an aperture |50, with the annular recess |46. A piston |5| is slidable within the extension |49 and has its right hand face in con.. tact with the sealing liquid. Its left hand face is subjected to the expanding force of a compression spring |52, confined in the extension |49 as by the screw plug |53. The pressure of spring |52 provides a supplemental pressure upon the liquid |41.

The manner in which the supplemental pressure is exerted on the liquid |41 may be varied. In the form of the invention illustrated in Fig. 1l, the non-rotary member |55 surrounds the shaft 51, as before. It has a recess |56 in which the sealing liquid |51 is located. This sealing liquid is in communication, as by a conduit |58, Y

to an elevated source |59 of sealing material. In this way gravity head imposes the supplemental pressure.

The lower end of the non-rotary member Illissbowninthisinstanceassupported bythe metal bellows lili. This metal bellows is shown as having an extended bottom flange Ill fastened in fluid tight manner to the top Il! of the casing ill.

What is claimed is:

l. In a submersible structure adapted to be submerged lnwell liquid, a casing, a shaft ex.- tending from the casing. a sleeve of yieldable material suported by the casing and formins between it and the shaft an annular space around the shaft, a liquid seal in said space, and means imposing a contractile force upon the sleeve.

2. In a submersible structure adapted to be submerged in well liquid, a casing, a shaft extending from the casing, a sleeve of yicldable material supported by the casing and forming between it and the shaft an annular space around the shaft, and a body of mercury in said space. said shaft being provided with a suitable surface at the sleeve, that is inert with respect to mercury.

3. In a sealing device for a submersible structure adapted to be submerged in well liquid. and having a shaft extending from the structure, a body of liquid forming a supplemental seal around the shaft, means forming a pair of axially spaced surfaces in sealing contact with the shaft and Joined by a yielding wall, said means and said wall together forming an annular chamber around the shaft for confining said sealing liquid, and means exerting a pressure in addition to `that of the liquid sealed against, upon said wall for increasing the iiuid pressure exerted by said body.

4. In a sealing device for a submersible stmotureadaptedtobesubmergedinwell liquid,and having a shaft extending from the structure, a non-rotary yielding member encompassing and contacting the shaft, said member forming an annularrecessaroundtheshaft,asealingliquid in therecess, and means exerting a compressive force around said yielding member to be effective upon the sealing liquid.

5.Inaseaiingdevice between a stationary memberandarotarymembenapairofaxially spaced non-rotary members in sealing contact with the rotary member. an intervening yielding membenabodyofliuiiidinsaidyieldingmember surrounding the rotary member and forming a nipplementai seal thereagalnst, means for urging said axially spaced members toward each other and means resiliently supporting the sealing device on said stationary member.

tlnasealingdevicearoundarotaryshaft extendingfromacasing.apairofaxiallyspaced non-rotary members in close contact with the shaft. an intervening yielding member Joining saidaxialiyspacedmembers,abodyofseali.ng liquid coniined by said yielding member and surrounding the rotary member. and means for urgint: said axially spaced members toward each o er.

'LInasealingdevice around arotaryshaft extendingfromacasing,apair of axiallyspaced non-rotary members in close contact with the a ilexible member surrounding the shaft, Joining one of the axially spacedl members fluid tight manner to the casing.

8. In a sealing device for a submersible struchaving a shaft extending from the strucstructure being adapted to be subr a predetermined diiferential with respect to the pressure of the well liquid adjacent the seal.

THOMAS G. MYERS. 

